This is a Phase I open-label, multicenter study to evaluate the safety, tolerability, pharmacokinetics (PK),Pharmacodynamic characteristics, immunogenicity and antitumor activity of JS207 in patients with advanced malignant tumor. The Recommended dose for phase II trial （RP2D） will be determined based on the safety, tolerability, pharmacokinetics.

Inclusion Criteria:

1. Patients with advanced malignant tumor confirmed by histology or pathology, failed by standard treatment, no standard treatment or no standard treatment is applicable;
2. Eastern Cooperative Oncology Group (ECOG) 0 or 1;
3. Life expectancy ≥ 12 weeks;
4. At least one measurable lesion according to RECIST 1.1;
5. Adequate organ function;

Exclusion Criteria:

1. central nervous system metastasis；
2. There is a pleural, abdominal or pericardial effusion that is clinically symptomatic or requires repeated management (puncture or drainage, etc.)；
3. Images in screening showed that the tumor surrounded important blood vessels or had obvious necrosis and voids, and the investigators believed that it might cause bleeding risk；
4. The presence of severe, unhealed or open wounds, active ulcers, or untreated fractures；
5. A history of significant bleeding tendency or severe coagulopathy；
6. The presence of poorly controlled hypertension；